The HIV scenario has changed during the last two decades in the clinical, the behavioral, and the basic dimensions of the disease. Data from mortality and morbidity reports underlines the magnitude of the disease among Puerto Ricans but do not show the variables that may be playing a role on the severe impact of the disease among our population. Our longitudinal and multidimensional approach to the study of the disease among Puerto Ricans, will allow us to assess and monitor main changes in the disease. Also, it will allow us to study the synergism of variables that may be affecting the outcome of patients by helping to explain some of the health disparities issues involved in this HIV population. For this renewal, we propose to expand the actual HIV Data Core to an HIV/AIDS SUBSTANCE ABUSE AND HEALTH DISPARITIES DATA CORE. This Data Core will continue to study the natural history of AIDS disease among the Puerto Rican population throughout the HIV Central Registry. We will continue studying and monitoring changes in the HIV epidemics in Puerto Rico and expanding the scope of the study to the health disparities issues of this disease in our population, specially in patients using injecting drugs. The other scope of our core is to continue serving as a core facility for development, management, and support to researchers doing feasibility, pilot, and major studies of HIV within and outside of the institution. This new structure reflects our responses and acknowledgement to the different reviewers' comments and suggestions from our consultants and members of the Advisory Board. The overall goal of the Data Core is to establish and consolidate the research infrastructure to provide data management and analysis to HIV/AIDS researchers and to continue monitoring changes in the spectrum of HIV/AIDS disease in the Puerto Rican population with a new emphasis in the health disparities issues of the disease and the interplay of HIV/AIDS and substance abuse.